1. Field of the Invention
This invention relates to a carbide rod or shank boring bar with an axial coolant/lubricating bore extending therethrough that is fitted with a steel head into which a pocket is founded to receive a cutting insert, and the bore communicates with the insert.
2. Description of the Prior Art
For purposes of this patent application, brazing will be considered as the oxide-free bonding of similar or dissimilar metals by a filler metal that has a lower melting point than the metals to be joined, but usually above 300.degree. F. The brazing alloys used to accomplish the bonding of parts is also known as hard solders. Usually brazing is accomplished by hand torch, however it may also be done by induction heating. When using the prior art ambient air method of brazing a flux is always necessary to effect proper brazing by removing impurities from the metal. In the presence of oxygen the flux will oxidize forming a contaminant crust that can plug up holes and bores as well as coat parts and lessen capillary action.
In the formation of large diameter carbide boring bars with axial lubricated bores and steel heads with dimensions over 1/2 the brazing of the rod and head have been accomplished without much difficulty in ambient air. However, in all instances the brazing technique which uses silver brass has left oxidized flux in the lubricating hole. This has required additional time and expense in physically inserted an instrument in the bore to clean it out removing the flux.
In addition in the past the process could not be adapted to anything less than 1/2" rods because the axial lubricating bores are so small that no tool could fit into the bore and accomplish the cleaning out of the bore. Thus carbide boring bars with axial lubricating bores and steel heads in small diameter heretofore could not be provided. Therefore when using a small diameter carbide boring bar and steel head the cutting insert mounted within the pocket portion of the head had to be externally lubricated when it was cutting metal.